TABLE 1.

Amino acid decarboxylase mutations and phenotypes of acid-evolved strains

Straina	Lysine decarboxylase		Arginine decarboxylase		Glutamate decarboxylase
	Activityb	Mutation	Activity	Mutationd	Activity	Mutatione
B11-1	−	cadC::IS5	−	adiY (C→G)	+
B11-2	−	Δ([cadA]–[cadC])c	−	adiY (C→G)	+
F9-2	+		+		−	Δ(gadX–slp)
F9-3	+		+		−	Δ(gadX–slp)
F11-1	−	cadC::IS5	+		−	Δ(gadX–slp)
F11-2	−	Δ([ghoS]–cadC)	+		−	Δ(gadX–slp)
H9-1	−	cadC::IS5	−	adiY ←IS5← adiA	+
H9-2	−	cadC::IS5	−	adiY ←IS5← adiA	+

^aStrains were isolated from the experimentally evolved populations B11, F9, F11, and H9 (13).

^bActivity is shown as follows: +, the decarboxylase system is active; −, the decarboxylase system activity is decreased or absent.

^cBrackets indicate that the mutation takes place in the middle of the gene. Delta symbols indicate deletion. En dash indicates that deletion includes all genetic material between indicated genes.

^dIS5 with double arrows (←IS5←) denotes the insertion of an IS5 element into the intergenic region; the arrows indicate the direction of transcription of flanking genes.

^eDeletion of most or all of the Gad acid fitness island: gadA gadX gadW mdtF mdtE gadE hdeD hdeA hdeB yhiD dctR slp.